Automatic pressure control system for pneumatic tires



Dec. 18, 1951 w, R. PAUL 2,579,043

' AUTOMATIC PRESSURE CONTROL SYSTEM FOR PNEUMATIC TIRES 2 SHEETS-SHEET 1 Filed Jan. 19, 1950 INVENTOR WillpamR Paul ATTORNEY Dec. 18, 1951 Filed Jan. 19, 1950 w. R. PAUL 2,579,048 AUTOMATIC PRESSURE CONTROL SYSTEM FOR PNEUMATIC TIRES 2 SHEETS-'SHEET 2 INVENTOR William R. Paul ATTORNEY Patented Dec. 18, 1951 UNITED STAT as PATENT oFFIcE AUTOMATIC PRESSURE. CONTROL SYSTEM .FOR PNEUMATIC. TIRES 'WiIIiamRZ Paul, Amarillo, Tex.

. Application January 19, 1950; SerialNo.--.139,375

4 Claims. (Cl.152-416) My present invention relates to pneumatic tires. and particularly to means for automatically controlling the pressure of such tires duringuse.

.The. importance of maintaining the proper dynamic balance ofthe-tire-and inner tube-assem- "bly for. each wheel withincertain limits specified by the -manufacturers is well known. When a tire is out of balance unevenwear, "shimmy or tramp results. One ofthe chief causes of such conditions maybe .non-dmiforminflation. Nonunifoifm inflation usually develops whilethe vehicle is traveling either from slow leaks or from heatconditions and the operatormaydrive many .miles beforeherealizs suchia condition exists.

Thus there has long been. needed some accurate automatic meanstfor maintaininghtire pressures uniformly constant duringthetdriving of pneumatictire vehiclesover the roadlor highway to protect the tires from either over or under infiation.

Itxis an object of'my invention to provides.

novel system,whereby during driving the pneumatictires are kept at substantially the; proper inflated pressures.

Another object is to provide in" an automatic tire "inflation system, an air reservoir connecting 'with each tire including a-condition responsive means for maintaining a proper pressure in the reservoir and the tires at all times.

Another object is to. provide an air reservoir,

apressure responsive electric switch and an e1ectricallydriven air pump for maintaining pressures in the air reservoir within proper limits to-maintain the pressure of each tire within the proper safe driving limits to therebyavoid over or under inflation: from leaks or excessive tire temperatures developed on the road.

A further object is to provide novel connections foreach wheel, whereby air from the res- =erv'oir= tank is'iree to pass into thetire tube through theconventional tire valve stem during' driving on'r'oacl.

Still'a further object istoprovide for changing tires-when necessary by'ha'ving connections "demountal'ole with the hub caps of the wheels.

Other objects and many advantages will appear from the following detailed description of one embodiment oflmy invention and the appended claims.

IInthetdrawihgs whereinthe several parts are each, given a .numeraland referred to throughout the description by such numerals:

Figure 1 is a semi-diagrammatic illustration .of; the; assembled parts applied to the chassis threaded nipple-313 of apart of theswivel elbow the brake druml3, seeFigure l.

- mechanism or Figure 4, with @the' added illustratiorrof one-sof the-airtube wheel archestsup- "ported on the-chassisside of the. fixed partoi' the brake drum.

Referring to the drawings and first with particular reference-tethe assembled view of Figure 1,.there is illustrated a vehicle chassis I II with the usual axles II and i2; brake drums i=3, wheels l4. andipneumatic tires 15. Each wheelmounts a hub cap 16 adjacentwhichis mounteda novel swivel elbow coupling I! mounted on the end-of a curvedstraphereinafter described. This coupling I1 is shown in detail in Figures 4 and'fifas hereinafter fully described.

Mounted on the chassis) is a tank l8 formed to mount an air blow-off valve l9 and pressure gage 21], a condition responsive means 2|, hereinaiter described-andconnections 22 and 23 to a power driven pump ensemble 24.

Atan. opposite side. of the tank l8 are four outlet connections 25, 26,. 21 and", each being coupled to-elongated sections of flexible tubing or .thelike, 29, 30, 3|.and 32respectivelyL, This tubing leads from each outlet connection to a coupling I I, supported in acurved strap or bracket 34, see Figures 1, 4.and 5. Each sectionof tubing 'is'identicallymounted. on theunderside of the curved zstrap 34, which is made. in twin sections.

The curved strap or bracket. 34 archesover the uppermost part of the tireunder theusual' fender ormudguards; not shown. Itlis formed withan opening-35 above-a T-headed base 36,.formeid from the innersection, welded, riveted or otherwise securedr to a'fixed or non-rotating part of At the beginning of the brackets curved top portion is .a .de-

tachableaconnection 31. The connection .31 may be .ofanyysuitableaform to facilitate separating the; sections" of. the, strap bracket 34 when the tubing-is disconnected from nipple 33. to changea tire or remove alwheel. As shownitmaybesdetackled by removing the coupling pin 31a, see F 8 3 v The curved strap 34 permits the air tubing to pass through openin and curve around the underside of the strap to its connection with the swivel couplings threaded nipple 33. The tubing is secured to the strap 34 by clips 38 on the underside of the hinged curved top part.

Swivel elbow coupling 17 The swivel elbow coupling comprises a pair of aligned cubiform blocks and 4| formed with hollow air tube coupling nipples, one of which is ring 41, which heads some form of packing, such as graphite, cotton or the like, and further serves tocoact with'the flange 48 of a packing nut 49. Thus arranged the cubiform block 4|} mayturn freely with respect to the cubiform block 4 l; The block 4| is formed with an axially extending pin 56 that is welded into a socket 5| in the free end of the strap 34 adjacent the center of hub cap I 6. From the nipple 42 of the elbow swivel coupling I! there is a section of air tubing 54. There are four such tube sections, one for each tire, and

they connect to the usual tire valve stem to supplyairto the tires I5 from the air reservoir tank lfl. Preferably the usual valve inside the 'stem is removed so that the tank l8 and air tubing connect direct to the tube interior, and the tank serves the function of a master or servodevice! 5 Air reservoir tank 18 V The tank I 8 connects with the several tires from outlet couplings 25, 26, 21 and 28 by air tubes 29, 30, 3| and 32 supported over the tires by the brake drum mounted curved straps 34. Pressure in the air tank i8 is maintained substantially constant at a predetermined value by means of a pressure release valve I9 and gage20,

acondition responsivemeans 2| and a pair of piston pumps connected to tank intake tubes 22 and 23. Fig. 2, comprises a cylinder open tothe inte- The condition responsive means, see

rior of the tankl8. The cylinder 60. houses a piston Bland a spring 62 coiled around a shaft -63 carrying the piston. The piston shaft 63 ex- .tends through a cap 64 over the end of the cylinder through a snap action switch actuating rock bar 65 to a headed ball joint connection 66. The rock bar 65 is hinged to a sliding make and break .bar 61-; This bar 61 is mounted on a guide track .61 One end of thebar .61 connects by leads 68 and 69 to a source of electric current, such as "the-battery. in the vehicle and the other end strikes against an arm 10 of a forked electrical connection 1|. From each tine of the connection 1| are electric cables 12 and 13 to an electric ,motor 14. Snap action of the rock bar 65 is provided by the spring 65 stretched over the end of the bar. The electric motor 14 has a drive pulley 15, Which through belt 16 drives a relatively large pulley 11 on either side of which are eccentric discs 18 and 19.

When the motor 14 is running it drives these eccentric discs and a pair of connecting rods 80 and BI connected between the said discs and the end of piston rods 84 and 85. These connecting rodsare arranged to alternately be moved with respect to each other thereby through the piston rods 84 and 85 driving the pistons 86 and}? in,

cylinders 82 and 83 connected to the inlets 22 and 23 of the tank l8.

Operation In operation the outlets to the air tubes 29, 36, 3| and 32 are open and maintain a pressure in the tires based on the pressure in the tank l8. The tank pressure in turn is kept within predetermined limits by the pressure responsive means 2|, which will operate as a function of temper- V ature and/or pressure and the blow-off valve I9.

Whenthepressure drops due to leakage the piston 6| is moved toward the tank by the spring 62 and the rock bar 65 snaps ofi-center to the position shown in Figure 3 to close the switch circuit and start the pump motor 14. The motor drives the pumps by means of the eccentric discs T8 and 19 and their respective connecting rods and 8|, until the pressure is again brought up to the required level and the piston 6| snaps the rock bar 65 so it imparts sliding movement to bar 61 back to its original circuit breaking position.

Obviously, if pressure becomes too great from heat causes or the like the valve l9 will bleed ofi such excess pressures, thereby proportionately reducing pressure in the tubes 29, 36, 3| and 32 and the tires l5.

Thus there is provided a novel automatic system of tire pressure control, which maintains substantially uniform pressures during driving over the road even though there may be some leakage or some excess pressures developed in the tires or the system. This provides for much greater safety and longer life of the tires as they are kept at a proper dynamic balance unless a blowout should occur. Of course the danger'of blowouts is greatly reduced by uniform pressure regulation. l I

Although the present invention is only described and illustrated in detail for one embodiment thereof, it is to be expressly understood that the same is not limited thereto. Various changes may be made in the parts and arrangements thereof, as-will now probably appear to others skilled in this art. Reference should be had to the appended claims for a definition of the invention. v

What is claimed is: r

1. An automatic pressure control system for a wheeled vehicle with pneumatic tires, said vehicle having a master air supply tank mounted thereon, said tank having a plurality of outlets, an air supply conduit connected to each of said outlets, wheel mounted swivel'air conduit couplings each connected to one of said air supply conduits for supplying air to the inner tube of the tire on its respective wheel, each coupling having two relatively turnable members formed -with air conduit connecting nipples the first nipple serving as an air intake from the outlets of said master air tanks through one of said conduits and the second nipple as an outlet connection to the inner tube, an inlet connection opening into said tank, an air pump connected to said'tank by said inlet connection, pressure responsive means controlled by pressure in said tank connected to said master tank, an electric circuit, an electric switch in said circuit actuated to open and closed positions by said pressureresponsive means, an electric motor in said switch circuit in driving connection with said air pump, said motor being actuated upon closing said switch circuit, thereby operating said air pump upon reduction in pressure due to leakage or the like, and. a blow ofi valve on the tank for reducing excess pressure developed in the tank from heat exchange conditions or the like.

2. In a system of pneumatic tire pressure control for a wheeled vehicle having a master air supply tank mounted thereon, said tank having a plurality of outlets and a plurality of inlets, a swivel air coupling connected between the tire of each wheel and one of the outlets of said tank, said coupling comprising a fixed part and a rotatable part, a tank pressure responsive means connected to said master tank, an electric switch having a switch arm operated by said pressure responsive means, separate conduits each connected to one of the outlets of said tank at one end thereof, and at the other end to the fixed part of one of said couplings, an electric motor, an electric circuit including said switch and said motor, said switch being operative to open and close said electric circuit, and air pumps connected to the tank inlets driven by said motor when pressure drops in said tank, thereby exhausting said pressure responsive means to complete the motor circuit.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,165,876 Heberling Dec. 28, 1915 1,855,101 Daneel Apr. 19, 1932 1,915,161 Jordan June 20, 1933 1,988,671 Stout Jan. 22, 1935 2,010,250 Appelgate Aug. 6, 1935 2,168,690 Uksila Aug. 8, 1939 2,213,539 Wiegand Sept. 3, 1940 2,473,502 Bard June 21, 1949 

